WEST AMERICAN PYRAMIDELLID MOLLUSKH. 



183 



ODOSTOMIA (lOL^A) EUCOSMIA, new name. 



=Oscilla insculpta (Carpenter) Keep, West Coast Shells, 1888, j). 52; not 

 Odostomia insculpta De Kay, 1843. 



Plate 20, figs. 10, 10a. 



Shell elongate-conic, subdiaphanous to milk-white. Nuclear whorls 

 deeply obliquely immersed in the first of the succeeding turns, above 

 which only the tilted edge of the last one projects. Post-nuclear 

 whorls somewhat contracted at the periphery, very strongly slopingly 

 shouldered at the summit, marked by three strong lamellar keels 

 between the sutures, of which the middle one is a little nearer to its 

 anterior neighbor than to the posterior, the latter being about as far 

 from the summit as it is from the median keel. The deep channels 

 between the keels and the shoulders are crossed by slender axial rib- 

 lets which have a protractive slant on the shoulder and are decidedly 

 retractive in the channels. Periphery of the last whorl marked by a 

 keel a little weaker than those between the sutures. Base short, well 

 rounded, narrowly umbilicated, marked by three spiral cords and a 

 slender raised thread about the umbilicus, the channels bounding the 

 peripheral cord and those of the base are crossed by riblets as on 

 the spire. Aperture large; posterior angle obtuse; outer lip rendered 

 angulated by the keels, thus showing the external sculpture within; 

 columella slender, very strongly curved, slightly reflected, provided with 

 a weak fold at its insertion; parietal wall covered with a weak callus. 



The type (Cat. no. 106501, U.S.N.Al.) comes from Point Abreojos, 

 Lower California. It has six post-nuclear w^horls and measures: 

 Length 2.5 mm., diameter 1 mm. 



The following specimens have been examined. 



U.S.N.M. 

 cat. no. 



No. of 

 speci- 



106501 

 105483 

 4(il75 

 129294 

 153091 

 105409 



Locality. 



Point Abreojos, Lower California 



....do 



Todos Santos Bay, Lower California. 



San Pedro, California 



....do .. 



San Diego, California 



Arch Beach, California 



San Pedro, California 



Disposition of 

 material. 



U. S. Nat. Mus. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Univ. Cal. coll. 

 Oldroyd coll. 



"Type. 

 ODOSTOMIA (lOLiEA) DELICATtJLA Carpenter. 

 Plate 20, figs. 5, 5a. 

 Odostomia (Evalea) ddicalula Carpenter, Ann. Mag. Nat. Hist., vol. 14, 1864, 



p. 47. 



Shell very elongate, ovate, crystalhne, transparent. Nuclear 

 whorls wholly immersed in the first of the succeeding turns, above 

 which only a portion of the last tw^o project. Post-nuclear whorls 

 well rounded, moderately contracted at the suture, strongly shoul- 

 dered at the summit, marked by five strong, well-rounded, equal 



